While this setup MIGHT reduce the restriction on the air intake, it also means you're pulling in hot underhood air rather than cooler outside air. Hot air is less dense than cool air, so you need more of it to make the same amount of power. So it's not clear how the gains and losses will balance out.

And I'm not sure what you mean by differentiating acceleration from horsepower. Newton tells us that force = mass x acceleration. In this case force comes only from horsepower, so you can't gain acceleration without adding power (except by removing weight).

They finished with 343hp, 684 ft lbs torque , 12.23 city and hwy combined mpg, 13.51 hwy mpg, didnt touch any internals of the engine, And that battleship of a truck is a crew cab dually centurion...

Interestingly, in a recent issue Fourwheeler included this project as one of the 10 worst projects in the magazine's history, citing the huge investment needed for what they described as relatively minor gains. Not sure that I agree with them, but it was interesting to note, especially when I see the project touted here so frequently.

Quote:

Originally Posted by joesluckyseven

I have also heard good things about switching to an HEI distributor as far as freed up power and MPG improvements.

HEI will give significant gains over an LEI (low energy ignition), but that hasn't been an issue in vehicles since sometime around 1980 (give or take a bit). All factory ignition systems since then have been pretty darn good, with very little room for improvement. If you are looking to squeeze the absolute best performance you can out of an engine, regardless of cost, it's a place you can throw some cash. But it's not a place for easy gains anymore.